Three-dimensional telomere profiles in papillary thyroid cancer variants: a pilot study

Abstract

Papillary thyroid carcinoma (PTC) has two main histologic variants: classical-PTC (CL-PTC) and follicular variant PTC (FV-PTC). Recently, due to its similar features to benign lesions, the encapsulated FV-PTC variant was reclassified as noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). Nonetheless, specific molecular signatures are not yet available. It is well known that telomere-related genome instability is caused by inappropriate DNA repair of dysfunctional telomeres and that mechanisms involved in the damaged telomere repair processing may led to detrimental outcomes, altering the three-dimensional (3D) nuclear telomere and genome organization in cancer cells. This pilot study aimed to evaluate whether a specific 3D nuclear telomere architecture might characterize NIFTP, potentially distinguishing it from other PTC histologic variants. Our findings demonstrate that 3D telomere profiles of CL-PTC and FV-PTC were different from NIFTP and that NIFTP more closely resembles follicular thyroid adenoma (FTA). There was no association between BRAF expression and telomere length in all tested samples. Our data indicate that 3D telomere profiles of CL-PTC and FV-PTC were different from NIFTP and that NIFTP more closely resembles FTA. NIFTP has longer telomeres than CL-PTC and FV-PTC samples, and that telomere length of NIFTP overlaps with that of the FTA histotype. These preliminary findings reinforce the view that NIFTP are lesions closer to non-malignant thyroid nodules and confirmed that short telomeres are a feature of PTC.